Digital Novel Markup Language is one of the first scripting languagegame engines for creating visual novels, also known as interactive fiction games. DNML was developed using C++ by a Japanese programmer known by his or her Internet name, Karin. The initial release was in 1998. The programming structure is similar to HTML, which made it easy to produce dōjin games. DNML was succeeded by software like NScripter, KiriKiri and Ren'Py.
KiriKiri
KiriKiri is a scripting engine by Japanese developer "w.dee", initially released in 1998. It is almost exclusively used with the KAGframework as a visual novel engine. Usually, the package of the two components is regarded as the whole engine, and referenced with major version numbers. Thus, the current version is called KiriKiri2/KAG3. It is available under the GNU General Public License, though commercial licenses can be acquired if somebody wishes to expand the software without disclosing the changes. KiriKiri has been used in both dōjin and commercial visual novels, the most well known of which are TYPE-MOON's Fate/stay night and Fate/hollow ataraxia. It is often used as a more modern and expandable replacement of the older NScripter engine. Another game notable visual novel that is known to be implemented using this engine is :ja:1999ChristmasEve. The Nekopara game series available on Steam also uses a modified version of Kirikiri. For KiriKiri2 and KirikiriZ's implementation of KAG there is a module called 鱧天. which provides a myriad of plugins and a ready made template to build games on. As TyranoBuilder is to TyranoScript, there are several programs which create a graphical editor on top of the KAG script. The most well known of these is NVLMaker. Which also has a cloud platform. Due to a lack of updates since October 2010, from 2013 onward the code has been forked and continued as Kirikiri Z.
NScripter
NScripter is a visual novel engine written by Naoki Takahashi. Due to its simplicity and its liberal license, it quickly became popular in Japan, and was used for a number of high-profile commercial and dōjin titles, such as HaniHani and Tsukihime. The original NScripter is closed-source and only available for Windows. A number of cross-platform clones have been written. The best-known NScripterclone is the free and open-source software implementation, ONScripter. Its popularity among the visual novel localisation community is attributed to the ease of modifying the engine to support languages other than Japanese. It strives to maintain compatibility with visual novels designed for NScripter. ONScripter is based on the Simple Directmedia Layer library, and can thus be used to run NScripter games on platforms supported by SDL, such as OS X, Linux, PSP and the iPod. ONScripter-EN is a branch of ONScripter that is maintained separately by the English-language community, for convenience and for ease of introducing enhancements that are suited to the community. PONScripter is a fork of ONScripter-EN. Its stated goal is to provide an easy porting target for translation projects, with emphasis on Western languages. PONScripter has made heavy modifications to the ONScripter-EN base code, and is deliberately backwards-incompatible. PONScripter was originally maintained by Peter "Haeleth" Jolly. Since September 2009, it is maintained by Mion of Sonozaki Futago-tachi, the Higurashi no Naku Koro nitranslation group. KScripter is a Flash-based scripting engine that was inspired by NScripter but uses ActionScript and SWF.
Ren'Py
The Ren'Py Visual Novel Engine is a free software engine. Ren'Py is a portmanteau of ren'ai, the Japanese word for 'love', a common element of games made using Ren'Py; and Python, the programming language that Ren'Py runs on. The easy to learn script language allows anyone to efficiently write large visual novels, while its Python scripting is enough for complex simulation games. Ren'Py has proved attractive to western hobbyists; over 1000 games use the Ren'Py engine, nearly all in English. Visual novels, kinetic novels, role-playing games, simulation games, and many other games can be made with Ren'py.
TyranoBuilder
TyranoBuilder is a commercial visual novel engine that supports creating projects as web apps, as well as native app for Windows, Mac, Android, and iOS. Most of its functionality are available via its GUI, without resorting to scripting. It is based on TyranoScript, which is a free web focused engine that is in Japanese, although a partial English version exists. The syntax which both TyranoBuilder and TyranoScript use is very similar to the scripting language of KirKirki, although not as flexible. A unique feature of TyranoBuilder is its support for Live 2D, which most other engines lack.
Suika 2
Suika 2 is a free and open source visual novel engine. It supports Windows, Mac OS, Linux, and Android. Owing to the way it is written it is very easy to port off other platforms. In terms of syntax it is a mix of Kirikiri and Nscripter, utilising a more traditional syntax. It is one of the few Japanese visual novel engines that natively support English text. When compared to other engines it is very simple, however a user can customize it with relatively little effort. It is notable for its extremely low hardware requirements, being capable of running smoothly in a system with no proper graphical acceleration. The engine was first released in 2001, being bundled with a visual editor similar in function to Tyranobuilder's GUI. Suika 2 was released in 2016, with all of its components being rewritten except for its image processing components. The engine can be downloaded from either its website or Github page.
NVList
NVList is an open source visual novel engine that runs on Windows, Mac OS, Linux, Android, and even online. It is coded in the Java language, even though the scripts are written in Lua. It is being updated to this day on Github. It has all the functionality required for a Visual Novel,and more. It has support for resolution scaling and switching. Along with pixel and vertex shaders.
